Some Perspectives on Enhanced Heat Transfer—Second-Generation Heat Transfer Technology

1988 ◽  
Vol 110 (4b) ◽  
pp. 1082-1096 ◽  
Author(s):  
A. E. Bergles
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Second Generation ◽  
Historical Background ◽  
Rapid Rate ◽  
Transfer Enhancement ◽  
Enhanced Heat Transfer ◽  
Structured Surfaces ◽  
The Past ◽  
Microfin Tubes

During the past twenty-five years, heat transfer enhancement has grown at a rapid rate to the point where it can be regarded as a major field of endeavor, a second-generation heat transfer technology. After some historical background, mention of the driving trends, and a review of the various convective enhancement techniques, four areas of major contemporary interest are discussed: structured surfaces for shellside boiling, rough surfaces in tubes, offset strip fins, and microfin tubes for refrigerant evaporators and condensers. The review concludes with developments in the major areas of application.

scholarly journals Diamond-Shaped Extended Fins for Heat Transfer Enhancement in a Double-Pipe Heat Exchanger: An Innovative Design

2021 ◽  
Vol 11 (13) ◽  
pp. 5954
Author(s):  
Muhammad Ishaq ◽  
Amjad Ali ◽  
Muhammad Amjad ◽  
Khalid Saifullah Syed ◽  
Zafar Iqbal
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Heat Exchangers ◽  
Adaptive Finite Element Method ◽  
Transfer Enhancement ◽  
Enhanced Heat Transfer ◽  
Frictional Loss ◽  
Special Cases ◽  
Double Pipe ◽  
Pipe Heat

Heat transfer enhancement in heat exchangers results in thermal efficiency and energy saving. In double-pipe heat exchangers (DPHEs), extended or augmented fins in the annulus of the two concentric pipes, i.e., at the outer surface of the inner pipe, are used to extend the surface of contact for enhancing heat transfer. In this article, an innovative diamond-shaped design of extended fins is proposed for DPHEs. This type of fin is considered for the first time in the design of DPHEs. The triangular-shaped and rectangular-shaped fin designs of DPHE, available in the literature, can be recovered as special cases of the proposed design. An h-adaptive finite element method is employed for the solution of the governing equations. The results are computed for various performance measures against the emerging parameters. The results dictate that the optimal configurations of the diamond-shaped fins in the DPHE for an enhanced heat transfer are recommended as follows: If around 4–6, 8–12, or 16–32 fins are to be placed in the DPHE, then the height of the fins should be 20%, 80%, or 100%, respectively, of the annulus width. If frictional loss of heat is also to be considered, then for fin-heights of 20–80% and 100% of the annulus width, the placement of 4 and 8 diamond-shaped fins, respectively, is recommended for an enhanced heat transfer. These recommendations are for the radii ratio (i.e., the ratio of the inner pipe radius to that of the outer pipe) of 0.25. The recommendations are be modified if the radii ratio is altered.

Enhancement of Natural Convection Heat Transfer by a Staggered Array of Discrete Vertical Plates

1980 ◽  
Vol 102 (2) ◽  
pp. 215-220 ◽  
Author(s):  
E. M. Sparrow ◽  
C. Prakash
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Transfer Enhancement ◽  
Parallel Plate ◽  
Convection Heat Transfer ◽  
Transfer Enhancement ◽  
Enhanced Heat Transfer ◽  
Maximum Heat ◽  
Maximum Heat Transfer ◽  
Parameter Ranges

An analysis has been performed to determine whether, in natural convection, a staggered array of discrete vertical plates yields enhanced heat transfer compared with an array of continuous parallel vertical plates having the same surface area. The heat transfer results were obtained by numerically solving the equations of mass, momentum, and energy for the two types of configurations. It was found that the use of discrete plates gives rise to heat transfer enhancement when the parameter (Dh/H)Ra > ∼2 × 103 (Dh = hydraulic diameter of flow passage, H = overall system height). The extent of the enhancement is increased by use of numerous shorter plates, by larger transverse interplate spacing, and by relatively short system heights. For the parameter ranges investigated, the maximum heat transfer enhancement, relative to the parallel plate case, was a factor of two. The general degree of enhancement compares favorably with that which has been obtained in forced convection systems.

Current Progress in Enhanced Heat and Mass Transfer

2012 ◽  
Author(s):  
Arthur E. Bergles ◽  
Raj M. Manglik
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat Transfer Enhancement ◽  
Heat And Mass Transfer ◽  
Transfer Enhancement ◽  
Science And Engineering ◽  
The Past ◽  
Current State ◽  
Active Enhancement

Heat transfer enhancement, which is often also referred to as augmentation or intensification, has evolved into an important component of thermal science and engineering. The accumulated literature in enhanced heat and mass transfer includes thousands of references, and it continues to grow. To give an overview of the current state of this important technology, representative developments over the past ten years in each category of enhancement techniques are cited and commented on. The discussion is divided into the literature, passive enhancement techniques, active enhancement techniques, and compound enhancement techniques.

Heat Transfer Enhancement During Pool Boiling of Water Over Horizontal and Vertical Tubes With Micro Structured Surfaces

2012 ◽  
Author(s):  
Jeet S. Mehta ◽  
Satish G. Kandlikar
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
High Speed ◽  
Pool Boiling ◽  
Bubble Nucleation ◽  
Steam Generation ◽  
Transfer Enhancement ◽  
Vertical Orientation ◽  
Structured Surfaces ◽  
Wide Range

Pool boiling is a stable and an efficient method for transferring large quantities of heat. This mode of heat transfer is used in a wide range of applications, including steam generation in boilers, petrochemical, pharmaceutical, cryogenic and many other industrial processes. It also holds promise for cooling of microelectronic devices, such as lasers, microprocessors and others. The objective of this work is to investigate the heat transfer augmentation due to an array of micro structured surfaces over a circular tube. The effects of horizontal and vertical orientation of the tubular test section on heat transfer enhancement are also studied. The bubble nucleation, growth and interactions over the micro structured surfaces are analyzed using high speed cameras to understand the bubble dynamics.

Study of heat transfer enhancement for structured surfaces in spray cooling

2013 ◽  
Vol 59 (1-2) ◽  
pp. 464-472 ◽  
Author(s):  
J.L. Xie ◽  
Y.B. Tan ◽  
F. Duan ◽  
K. Ranjith ◽  
T.N. Wong ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Spray Cooling ◽  
Transfer Enhancement ◽  
Structured Surfaces

scholarly journals Numerical Study on the Influence of Vortex Generator Arrangement on Heat Transfer Enhancement of Oil-Cooled Motor

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6870
Author(s):  
Junjie Zhao ◽  
Bin Zhang ◽  
Xiaoli Fu ◽  
Shenglin Yan
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Transfer Enhancement ◽  
Vortex Generator ◽  
Attack Angle ◽  
Vortex Generators ◽  
Dimensionless Number ◽  
Transfer Enhancement ◽  
Enhanced Heat Transfer ◽  
Longitudinal Distance

At present, vortex generators have been extensively used in radiators to improve the overall heat transfer performance. However, there is no research on the effect of vortex generators on the ends of motor coils. Meanwhile, the current research mainly concentrates on the attack angle, shape and size, and lacks a detailed study on the transverse and longitudinal distance and arrangement of vortex generators. In this paper, the improved dimensionless number is used as the key index to evaluate the overall performance of enhanced heat transfer. Firstly, the influence of the attack angle on heat transfer enhancement is discussed through a single pair of rectangular vortex generators, and the results demonstrate that the vortex generator with a 45° attack angle is superior. On this basis, we compare the effects of different longitudinal distances (2 h, 4 h, and 6 h, h meaning the height of vortex generator) on enhanced heat transfer under four distribution modes: Flow-Up (FU), Flow-Down (FU), Flow-Up-Down (FUD), Flow-Down-UP (FDU). Thereafter, the performances of different transverse distances (0.25 h, 0.5 h, and 0.75 h) of the vortex generators are numerically simulated. When comparing the longitudinal distances, FD with a longitudinal distance of 4 h (FD-4h) performs well when the Reynolds number is less than 4000, and FU with a longitudinal distance of 4 h (FU-4h) performs better when the Reynolds number is greater than 4000. Similarly, in the comparison of transverse distances, FD-4h still performs well when the Reynolds number is less than 4000, and FU with a longitudinal distance of 4 h and transverse distance of 0.5 h (FU-4h − 0.5h) is more prominent when the Reynolds number is greater than 4000.

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